A variety of data entry techniques have been developed to enhance usability and to make computers more versatile. A typical computing environment, especially a computing environment incorporating graphical user interfaces for user interaction, may be optimized for accepting input from one or more discrete input devices. As an example, an individual may enter characters (i.e., text, numerals, and symbols) with a keyboard and control the position of a pointer image on a display with a pointing device, such as a mouse or trackball. A computing environment incorporating graphical user interfaces may also accept input though one or more natural input methods, including speech input methods and handwriting input methods. With handwriting input methods, a pen-like stylus may be utilized to serve the general purpose of a pointing device and to create electronic ink.
Conventional stylus-based input devices are passive or active. A conventional passive stylus provides a tip that applies pressure to the surface of a touch screen apparatus. A conventional active stylus includes electronics that interact with its computing environment to determine the location of the stylus on the writing surface, which rely upon acoustic, magnetic or induction technology to determine the location information.
Conventional computing systems that interact with stylus-based input devices are designed to accept input from a single stylus-based input device at a given time. These conventional systems do not uniquely identify individual stylus-based passive input devices. Further, these conventional systems do not react differently to inputs from different passive stylus-based input devices, such as providing different types of digital ink, depending upon the input device being used.